S-91259A660 5/16"-18 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional durability with 140,000 psi tensile strength and 84,000 psi shear strength, ideal for high-stress industrial applications
• Superior corrosion resistance from the black oxide finish, extending service life in harsh environments
• Precise alignment and reduced wear due to the 6-1/2" shoulder length with tight tolerances for stable component positioning
• Reliable thread engagement with Class 3A fit and coarse UNC threads, ensuring secure fastening and vibration resistance
• Easy installation and removal with the hex socket drive and knurled head for improved grip during tool use
• High material integrity from alloy steel with Rockwell C32 hardness, offering consistent performance under load
• Compliance with industry standards including ASME B18.3, RoHS 3, and REACH, guaranteeing quality and environmental safety

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in precision machinery, such as maintaining alignment in rotating assemblies and reducing friction in pivoting joints. The black oxide finish provides a protective layer against rust and corrosion, making it suitable for automotive, aerospace, and heavy equipment applications where exposure to moisture and chemicals is common. With its 6-1/2" shoulder length and tight diameter tolerances, it ensures accurate spacing and support for components like gears and bearings, minimizing misalignment and wear. The UNC coarse threads and Class 3A fit deliver strong, vibration-resistant connections, while the socket head design with knurling allows for efficient installation in confined spaces. By combining high tensile and shear strength with robust material properties, this screw enhances reliability in demanding environments, reducing downtime and maintenance costs.

Specification Summary & Compliance

This shoulder screw adheres to precise dimensional standards, including a Class 3A thread fit for superior accuracy and a shoulder diameter tolerance of -0.004" to -0.002" with length tolerance of -0.005" to 0.005". It conforms to ASME B18.3 specifications and is manufactured from alloy steel with a black oxide finish. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) ensures it meets environmental and safety regulations, supporting sustainable procurement practices.